and I can tell you you need to be above the withdrawal threshold and have at least double your free roll earnings to have the captcha removed based on experience. If you want proof make a new account and send some coins to it but under the withdrawal threshold and you will still have to do the captcha to claim. It isn't something I can easily prove with my account though since I just passed 15k free roll earnings which means I will always be above the 30k threshold with double the balance.
If that's the case then it's an additional requirement that the site owners have not stated. The original post I corrected just said that 30,000 was the requirement when actually the requirement is double your total free roll winnings.
I'm not going to get banned for multi-accounting to prove it, I'll just believe you as setting a threshold like that makes sense.